SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0fecaa71b4d174260dc402556460df15a1ea19d8adc444f5b0f32aa60772969' 
  AND token = 'D/2+8NQQt7eFetzdj1FBcFdWOqDPXVi9JMEXs/uxRPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}