SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e3633df52f5c776dde48ee601c44f058afacfb11226e39905754edb585358c3' 
  AND token = 'u6JuHRPCqrqYpQKD+ld4luxwk5FMVNrCH9qoo1+jBAM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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