SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dba3c72ac843aed0278cf242f092e568c5e5af2e28b3840ac074f95dcf009ffb' 
  AND token = 'rNzwWI3+NRUPO2pJWwNwP6rhh+xYZDZOPOY7X5CChNY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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