SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5059952ac32d69046f682959aeed04592663add9ef5b14968a159999516a8e2' 
  AND token = 'FqbWrCEr5SUswvE9WFJ9BvgjB3f+oPfDXprGhD5kL4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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