SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61bd18c0945ea6690e1f5525e38ac0678c5d4b4d4ae010ec07fa86ee55f2ea3' 
  AND token = 'Iw9EVLH5wNwStF7Q8V6EX93UbnIkhWbJJn/icQ1mS3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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