SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0e4c094a98e3f18388c18ee0f237ec74cb94fef1bb4ce9b4fe934dc94f8b374' 
  AND token = 'NDQVLfO9SsmyMSUUAmBbfTAgWW0+kRePJRZVfxWr7VY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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