SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b2ef96644d7d6df01571e57cd9c56c0afe1a39630b584eacc5c5f26e833428c' 
  AND token = 'bJ18g55eYQIrTWTIAGiN5J6mLWXIxKSikb+OGKVPFiI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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