SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '004f55a73fe5b9971063b63dac93fdecd5ccf771b2c07a2e51bf6afd43b09295' 
  AND token = 'Fq5r/3V1trLlBwoZ/pO7hjeAGfEqSFnSeIliBvQ8kYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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