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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '56671d7cd6181d58144dc4c8a66a9df90cf3bed1100dce70c152abe038c3b0ab' 
  AND token = 'vQJ8CjN1IRu5JK3RZ0d8ksr/JW2bZ/QsSvmU0UCuA64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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