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SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '257e2d89a09e2e4dd7aa68b3c19e1758ddccb3cb985408b7feb4d092f73c4ca2' 
  AND token = 'v4zmFQeksatlxdXGNjIV5goxvVdoy6LrbXVT3ZWX/yQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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