SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73e8e845dd95324f3bd8cfe3d5df6b5515dd29c541207bb42ee022b37c4339be' 
  AND token = 'QoNHAESuTR02/8fDX0ewOdFRUrdKV1D5T1cTU/hceNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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