SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb271c2880278115c419dc7e1a905abdf1315d7147ddd59c6511aa310b2b2796' 
  AND token = 'Qt9ZZvF1auNnEianvUFZoLRIX2P4dbRkdat+Vu1PQh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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