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SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '05be2355c27db01416ebee8436ea1bd7e0781eb736f0e70471d552462238181d' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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