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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a8ce715792ee12fe0f11a19d5f9bcadf1f4702a1fdee0c8dbd7a0d923fc75a07' 
  AND token = 'rR7C1u90lz0JMPMyNtB+9fI/M78h3j8Nffh6rJZcELc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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