SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29fb624304ba48705759beda413598aa294ad602fb2d08ae3047e4e145c4f5d4' 
  AND token = '1eHy9VfhXbsC/J0Jp8IP/fFde/izEpSpoEfdFiRdfaY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}