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SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3deb198c5e6b7fbd3b7a7ebb7c25179bdecc0bb617aa850c6fe3864585b10c7a' 
  AND token = 'cNp6LbOqTIBXAwh/gIz4BiUEY/5gxWJBTlIcnX2NtNA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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