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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b5e5a2b9ca19b97be16ca710781b4f6c3dce1e25ca66dc5d8f5a59a2575e682f' 
  AND token = '4r4AwGftBU+I0JRmgDjdGDddYxNecdmo8j2hdUu8T+Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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