SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ad9a0b57da59ec85b2b10a8d3920e1a8a85da3426d0b68fd0dbf4276190fe2a' 
  AND token = '6l78x30f55rkEsDBfCsEM2MkKPdJUYn1phnLtTl81HY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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