SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc477cd4c96a302a661166bc63ad667f7e5192f006a5df9d872e57a28a64de83' 
  AND token = 'qyyOAyPRA9K2RivSjbuXZm3BnQDvQb1XZpEjBadfLB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}