SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'd3921aa55e44b50b0e7d2bacae256681249de2c02e7559fbfa1d8a3e565f8f43' 
  AND token = '+zAaSR3MOsruLL/m8u947qygVXwRmZ186rcE6qFFhwo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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