SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '419a0bc6458b75b750d422bf9610e4edcdb428cfe2b560e854a961a26da40e5e' 
  AND token = 'idpUCA7y7I+9zOvcUtnW7sh2QIJGW+0KS9lURD3t5yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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