SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7c7d835f0469055944cbf6b0555fb3a1e29ac50993bf6592dbf367e05ddccb2' 
  AND token = 'zS+FDrp6Bjyj/0t8UcXdS6mqhoCigglKrGZVqPgkYeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00197

JSON explain

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